Uneven lighting in cycles render
Difference in lightning does Material 2 - Magic texture.
This node generates black material on some faces differently, depence on object position.
On the left side are black back sides of object on the right sides are black front sides of objects.
Disabling node from node tree fix the lightning issue.

Node attached into Normal socket generates blacks on all negative XYZ axis directions.

I don't know what is a proper way, but ussally you should plug node into Color socket. So try this.

Plus as already mentioned - you have overlaping objects with different materials. But even I kept only one side and Mirrored with modifier, issue was there.